This invention relates to ruminant feeds and feed supplements containing protein and protein equivalent nitrogen which releases at a slow and substantially even rate in the rumen of cattle, sheep, or other ruminating animals. More particularly, it relates to a new method for converting fermented proteinaceous agricultural products and wastes to ruminant feeds, having properties of slow nitrogen release, by reaction with liquid carbamides and aliphatic dicaroxylic acids.
Ruminants such as cows, sheep, and goats form a special class of animals because of their digestive systems. Ruminants have a complex stomach which consists of several compartments. The first compartment, known as the rumen, contains numerous microorganisms which break down ingested proteins and amino acids into other compounds, such as ammonia. The ammonia is simultaneously synthesized into microbial protein in the rumen for digestion and absorption further down the digestive tract.
The rapidity with which the microorganisms in the rumen break down the ingested nitrogen compounds has limited the efficiency with which a ruminant natural proteins and severely limits the amount of synthetic nitrogen compounds which may be fed. Urea is the most common synthetic nitrogen compound fed to ruminants. Urea is degraded to ammonia and carbon dioxide very rapidly by the Urease enzymes present in the rumen. When urea is fed at a rate appreciably higher than the rate at which ammonia can be effectively utilized by the animal, the ammonia concentration in the rumen increases rapidly causing toxicity and frequently death.
It has been long postulated that an important improvement in feeds for ruminant animals would be achieved if a feed containing large amounts of low cost protein equivalents could be prepared which would release them at about the same rate the animal could safely utilize them.
There has been no successful method for combining the relatively low level and generally insoluble natural protein in fermented agricultural by-products and wastes with the low cost synthetic nitrogen chemicals such as urea, to produce a slow-releasing ruminant feed product. There have been several not completely successful efforts to dispose of fermented agricultural wastes in innocuous forms into the environment, but no product has been found which can be economically produced, shipped, and effectively fed to ruminant animals and at the same time solve a serious pollution or waste disposal problem for the industries producing very large amounts of fermented agricultural wastes.
Fermented agricultural products is used here to describe materials which were grown as vegetable, forage, or grain crops and which have been fermented by natural or industrial processes. The fermented agricultural products may be materials having appreciable value, such as corn silage, but they would usually be materials considered wastes such as municipal garbage and cattle feed lot manures.
Efforts to effectively use fermented agricultural products such as municipal garbage and manures as protein enriched feed supplements have not been successful to date. Corn silage is widely used as a feed for ruminant animals, but it has not been possible to react the silage with urea to produce a crude protein enriched feed with slow release properties. Problems with these products have been primarily caused by poor palatability and toxicity caused by incomplete or poor reaction of the synthetic nitrogen chemicals, such as urea, with the chemicals produced by fermentation of polysaccharides in the agricultural products.
Although the technology for separating municipal garbage mechanically into components for recycle of valuable components, such as paper, metals, and plastics, no method has been devised for the use of the organic portion of the garbage. This material has until now constituted a troublesome and expensive disposal problem.
An important improvement in ruminant feeds would be obtained if feeds containing high crude protein equivalents could be produced from low cost synthetic chemicals such as urea and fermented agricultural products and wastes, which would release the protein and protein equivalents at substantially the same rate at which they could be effectively and safely utilized.
To be effective, the process would leave the natural materials such as amino acids in such a condition that they could be digested and absorbed in subsequent parts of the gastrointestinal tract, such as the abomasum and the small intestine, and the process would convert the fermented and normally putrescible agricultural wastes to a feed which would be highly palatable to ruminant animals.
Several attempts to achieve such a process for producing ruminant feeds have been made by those in the art with none of the processes providing satisfactory controlled release of ammonia from the urea or other carbamides without damaging the agricultural product, or by-product feedstuffs in the product. An even greater problem has been the poor ruminant palatability of the products of the prior art processes.
Encapsulation of synthetic nutritive chemicals has been attempted. The aim has been to have the capsule dissolve slowly in the rumen and release the capsule contents primarily in the abomasum. No effective encapsulating agent has yet been found. Although technique might have merit for treating costly materials such as methionine, processing costs preclude improvement of commodity materials such as urea, biuret, corn silage, municipal garbage, or feedlot manures.
Other methods now used for combining synthetic chemicals with feedstuffs involve mechanical blending of the solid materials, and blending liquid chemicals or aqueous solutions of the chemicals with feedstuffs. The normal method involves blending of the materials and providing little or no reaction or protection of the synthetic chemicals, so that they are released almost instantly in the rumen. The toxicity of simple synthetic nutritive chemicals severely limits the amount of these low cost materials which can be safely used. For example, urea is normally used to substitute for only 3-15% of the protein intake of cattle on feed.
When the solid or liquid materials are heated with feedstuffs, the present practice is to heat in a drum dryer, such as an alfalfa dehydrator. The amount of contact between the natural feedstuffs and the synthetic nutritional chemicals is limited unless the material is held in the drum for an extended period of time. Material retention in an alfalfa type dehydrator is about 5-20 minutes. This extended retention time severely limits the temperature, which may be used to carry out reactions, because the feedstuffs will be degraded. In dehydration of natural feedstuffs, such as alfalfa or corn plant, caramelization of the products is a common problem. The heat-time combination of present drying techniques, which might be used to carry out reaction of nutritive chemicals, causes the caramelization which decreases the palatability of the feeds, frequently to the point of reduced animal feed consumption. Reduced consumption, of course, means slower animal growth rates, and increased animal production costs.
However, none of the aforementioned methods have been used successfully to react carbamides, such as urea with fermented agricultural products and wastes to produce palatable ruminant feeds which release nitrogen, protein equivalents, slowly for effective utilization by ruminant animals.
The animal feed industry has sought, without success, a practical method for preparing palatable animal feeds which release protein equivalents slowly and effectively utilizing carbamides without danger of toxicity and fermented agricultural product and wastes. A method for upgrading and safe utilization of waste by-products from agricultural industry has also been long sought after, because these wastes are objectionable or dangerous discharges to the environment, and the low feed value and non-palatable content of wastes has to now precluded use.